package com.manong.utils;

import com.manong.entity.Department;
import org.springframework.beans.BeanUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

/**
 * 生成部门树
 */
public class DepartmentTree{

    /**
     * 生成部门树列表
     * @param departmentList    部门列表
     * @param pid               父级部门ID
     * @return
     */
    public static List<Department> makeDepartmentTree(List<Department> departmentList,Long pid){
        //创建集合保存部门信息
        List<Department> list = new ArrayList<Department>();
        //判断部门列表是否为空，如果不为空则使用部门列表，否则创建集合对象
        Optional.ofNullable(departmentList).orElse(new ArrayList<Department>())
                .stream().filter(item -> item!=null && item.getPid() == pid)
                .forEach(item ->{
                    //创建部门对象
                    Department department = new Department();
                    //复制属性
                    BeanUtils.copyProperties(item,department);
                    //获取到每一个item的下级部门，递归生成部门树
                    List<Department> children = makeDepartmentTree(departmentList, item.getId());
                    //设置子部门
                    department.setChildren(children);
                    //将部门对象添加到部门集合中
                    list.add(department);
                });
        //返回数据
        return list;
    }
}
